I've found I can be hydrated when I awake, as first thing in the morning, I will urinate and my urine is clear, yet I still feel tired, rough and exhausted; kinda like suffering from a hangover, although I don't drink alcohol.
Normally, a hangover occurs due to the loss of electrolytes as a result of urinating more frequently than normal due to the level of fluids consumed.
During normal circumstances, a person with a functioning bowel and consuming a normal level of fluids through-out the day, will be absorbing fluids and the essential electrolytes from the digested food within the bowel as they sleep; a task us J pouchers can no longer achieved, hence the electrolyte deficiency.
I have a habit of adding salt to almost all my meals. I like the taste of it on my fruits, veggies, I also supplement potassium once in a while. Maybe that is keeping in check the electrolytes . I usually prefer more salt than others in all my meals. But I dont understand how dehydration can cause so much fatigue. I wanted to know because whenever I've aksed my surgeon he said jpouchers mostly suffer from iron and B12 defficiency. For electrolytes he just said drink a lemonade or a rehydrating drink if you feel like but thats highly unlikely.